In the locksmith art it is often necessary to determine the depth of cut of existing keys. This may be necessary, for example, in identifying a particular lock associated with a key, for making tumbler pins of the correct length, or for many other reasons. One important use is the determination of correct (or incorrect) cutting on a key machine to assure proper operation of the key in its associate lock. Some keys, for example, must have the cuts within 0.002 inch of the correct value in order to operate a lock.
One device currently available for use by a locksmith in determining key cut depth is a special micrometer unit, such as depicted as FIG. 1 herein. A generally C-shaped yoke has a permanently affixed knife-shaped edge to engage the cut of the key. A screw-type micrometer is positioned so that the flat end thereof will bear against the edge of the key opposite the cuts. The depth of cut is then read from the barrel of the micrometer. In order to have meaningful depth values, the same amount of torque must be applied to the micrometer for each of the key cuts. Although useful information can be obtained with such a unit, use of the device is very time consuming. Also, considerable care must be exercised in order to read and then record the information. This is particularly true since the key must be held while the micrometer is rotated to a given torque. Furthermore, this device is very difficult to use in determining cut depths of keys having cuts in both edges.
Accordingly, it is an object of the present invention to provide a gauge for quickly and easily determining the depth of cuts in a key.
It is another object of the present invention to provide a reliable and quickly operated gauge wherein the depth of cuts can be determined for keys having cuts on opposite edges thereof.
Another object of the present invention is to provide a gauge that will permit determination of cut depths of keys having a very close spacing between a shoulder and the cut closest to that shoulder.
A further object is to provide a gauge that can also be used to measure the pin lengths needed in a tumbler of a lock.
Still another object of the present invention is to provide a gauge for determining the depth of cuts in a key that is easily "zeroed" and easily read for ascertaining the depths.
These and other objects will become apparent upon a consideration of the accompanying drawings and the detailed description of the same, which follows.